The Leveling of the High Medieval Viennese City Moat A Space Syntax Perspective Claudiu SILVESTRU Vienna University of Technology Abstract: The present day street layout of the Viennese city center roots in the urban expansion of the 13 th Century. Among several measures involved - such as the erection of a new fortification ring and the inclusion of historically and economically important streets – the new urban area caused also the placing out of operation of the high medieval fortifications. The wall dates back to the roman period of Vindobona and was restored in the 12 th century by the Babenberg dukes. After becoming obsolete, the wall was partly incorporated between new houses as a fire-proof-wall and partly demolished. Nevertheless the rough course of the roman respectively high medieval wall is easily identifiable both in the late medieval and the present day urban layout. This paper focuses on the consequences on the overall street pattern that were introduced by the placing out of operation of the high medieval fortification and the leveling of its moat. In doing so, it will apply Space Syntax analysis methods to a new reconstruction of the plan of late medieval Vienna. The Space Syntax Theory was developed in the 60s by Bill Hillier in order to link urban patterns to social behavior and human movement. The employment of Space Syntax Analysis will point out the change of integration and centrality within the urban fabric caused by one of the most meaningful interventions in Viennese urban history. It will also depict the expansion process within the high medieval city and illustrate the meaning of distinctive areas such as the one around the St. Ruprecht’s church or the main square at Hoher Markt . This paper is part of current PHD-research on the urban development of medieval Vienna and new means of interpretation and presentation of the medieval Viennese cultural heritage. Keywords: Space Syntax, urban development, movement patterns Introduction The street pattern of the Viennese Inner city roots in the 13 th century petrification (GAISBAUER et.al. 2003: 134) and expansion (MITCHELL 2013:385) from a high medieval town to a late medieval city. This process increases the urban area by ca. 450% and leads to a multifunctional system with specific districts. In this context the area which formerly separated the town from its surroundings – the fortification area with the reinstated roman wall and city moat – becomes a valuable junction between the high medieval core and its extension. The paper at hand analyzes the meaning of the leveling of the fortification and the inclusion of this area in the overall urban system of the 14 th century by comparing it to a hypothetical model of 14 th century Vienna with a preserved separation between high medieval center and late medieval development area. The first part briefly describes the historical development of Vienna and its fortification system up to the late Middle Ages. The second part presents the results of a comparative Space Syntax analysis conducted on International Conference on Cultural Heritage and New Technologies | Vienna | 2013 the street pattern of 14 th century Vienna resp. a hypothetical street pattern with preserved high medieval fortifications. This research illustrates the consequences of the leveling of the Viennese city moat and the development of new urban areas on the overall street pattern and depicts the character of the distinctive zones within the high medieval town. Historical Development Vindobona Between the 1st and the 5th century AD the roman castrum Vindobona occupies the core area of the Viennese first district (fig.1). The proximity of the Danube and the steep slope is a great advantage in terms of traffic and natural fortification, securing the northern side of the area. The fortification system includes also moat, enclosing the remaining three sides. The roman military settlement is surrounded by a 2-3m strong stone wall (HUMMELBERGER & PEBALL 1974: 10) with several towers and four gates distributed along via principalis and via decumana / via praetoria . Because of a landslide the initial regular layout is altered resulting in a trapezoidal shape. The decline of the Roman Empire and the drop in population figures lead to a civil use of the enclosed military area by the inhabitants of the surrounding civil settlement. Even so, the vast extent of the castrum and its functional diversity exceed the needs and the maintenance possibilities and result in its abandonment in the 5th century. The early medieval settlement Archeological research dates back the earliest traces of a medieval settlement in the area of the former castrum Vindobona at the turn of the millennium. Because of the reduced functional diversity and the poor population figure the early settlement can’t occupy the whole area. In order to satisfy the primary requirement of safety, the core develops in the north-east corner. The acute angle which has resulted through the landslide offers a protective area easier to defend. Its center is articulated by precursory construction of later Romanesque St. Ruprecht's church. Recent archeological research identified a second early medieval development core in the area of later St. Steven's Cathedral (OPLL 2010). According to the state of the art in Viennese early medieval history research, the settlement at the turn of the millennium must have had a truly rural character. It is an easy to defend compact settlement in the north-east corner surrounded by some fragments of the massive roman fortification wall. The remaining area of Vindobona offers probably a post-apocalyptic image such as those that will be cherished later in the 19 th century as romantic. On the early medieval settlers wild nature taking over the monumental foreign stone ruins must have left a quite frightening alien impression. Even if the extent of preservation and reusability of roman structures can’t be estimated, the shape of the formerly enclosed zone is definitely a reference point for the development of the early medieval settlement. Up to the half of the 12 th century it expands concentrically and fills the area of the former castrum . 2 Silvestru – The Leveling of the High Medieval Viennese City Moat Fig. 1 – Vienna development stages and parameters (Copyright: Claudiu Silvestru) The first medieval town A massive turning point in Viennese history occurs in the 12 th century when Babenberg Heinrich II Jasomirgott becomes Austrian duke and relocates 1156 his residence from Klosterneuburg to Vienna. By now the settlement has expanded to become a high medieval town occupying the area of the former roman castrum Vindobona and includes several sacral (St. Ruprecht's church, St. Peter's church, St. Steven's church) and administrative (i.e. the court house on the Witmarkt ) buildings among organically scattered granges (CSENDES 2001: 71, 72) . With perishable wood still being the main building material and street facades not building alignments, urban history research can hardly make statements about the street layout. Only the accesses to the urban area provide a hint at the overall structure. Moving his court to Vienna the duke rehabilitates the roman fortifications (MOSSER n.d.), however modifying the location of the gates. The nine accesses are distributed asymmetrically, even some of those close to the axis being located just next to the roman gates. They indicate an irregular, organic street layout whose singular correspondence with the 3 International Conference on Cultural Heritage and New Technologies | Vienna | 2013 roman pattern seems to be the porta decumana / Peilertor and the porta principalis sinistra (PERGER 1991: 30) . The duke settles his court in the south-west corner of the area of the former castrum – an area known even today by the name Am Hof (at the court). Next to his palace, just outside the fortifications he founds a Benedictine monastery, introducing a new function in the urban system which will blossom starting with the 13th century. The only other archeologically documented built structure outside the reinstated city wall is a precursory church of later St. Steven’s. Nevertheless the location extra muros indicates some outskirt settlement areas. The late medieval street pattern of Vienna The structure of the late medieval public space of Vienna originates in the urban development of the 13 th century. Soon after the Babenberg dukes relocate their residence to Vienna the area of the former roman castrum becomes insufficient for the developing city. Financially sustained by the ransom for Richard I Lionheart King of England duke Leopold VI decides to raise a new city wall, including existing settlement structures around the high medieval town and expanding the urban area by ca. 450%. Through the 13 th and 14 th centuries the new intra muros area is densified, resulting in aligned street facades. At the same time stone replaces wood as the main construction material, leading to a street pattern preserved almost unchanged up to the modern age and in its main features even until today. Continuing a process which began several centuries before, the urban development of the 13 th century is also characterized through an increase of functional diversity. In addition to St. Steven's church two more parishes are founded with the newly built St. Michael’s church resp. the existing church of the Benedictine friary of the Scots as their centers. The spiritual life of the city is also shaped by the mendicant orders (Augustinians, Franciscans, Dominicans, and Carmelites) that move into the city and raise new monastery complexes. Through the foundation of the university and the certification of the theological faculty in the second half of the 14 th century Vienna gains its place among the elite of late medieval city. From a structural point of view the development of public space is determined by several parameters, some of the most important being the streets of Kärntner Straße / Rotenturmstraße and Hochstraße as well as the area of the former roman fortifications.